Lipscomb, William Nunn, Jr. ( born Dec. 9, 1919 , Cleveland, Ohio, U.S.—died April 14, 2011 , Cambridge, Mass. ) American physical chemist who won the Nobel Prize for Chemistry in 1976 for his research on the structure and bonding of boron compounds and the general nature of chemical bonding.

Lipscomb graduated from the University of Kentucky in 1941 and earned his Ph.D. in 1946 from the California Institute of Technology. He worked as a physical chemist in the Office of Science Research and Development from 1942 to 1946 and then joined the University of Minnesota as assistant professor. By 1959, when he left the university, he was professor and chief of the physical chemistry division. He then became professor of chemistry at Harvard University, where he served as chairman of the department of chemistry from 1962 to 1965. By developing X-ray techniques that later proved useful in many chemical applications, Lipscomb and his associates were able to map the molecular structures of numerous boranes and their derivatives. Boranes are compounds of boron and hydrogen. The stability of boranes could not be explained by traditional concepts of electron bonding, in which each pair of atoms is linked by a pair of electrons, because boranes lacked sufficient electrons. Lipscomb showed how a pair of electrons could be shared by three atoms. His theory successfully served to describe boranes and many other analogous structures.